From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from madrid.collaboradmins.com (madrid.collaboradmins.com [46.235.227.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AEB30F51F; Mon, 12 Feb 2024 08:49:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=46.235.227.194 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707727766; cv=none; b=NCPOHg0UYrVtCIQxukjOu+GYO4/1GiA73U9GABwMnuG+i6WIo09RUjE68eAjM3xvJ3tqsgnnpyEuZlEGVQ6CPTaq4oU3ImAZyOnaeDqSsKAmGPNnyWwDgvAgv3baKfW2trxFKcs6Qia1A5+0mmSRIrW0uurwKUYY3lP/fo3aDlI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707727766; c=relaxed/simple; bh=1VsQ4z1r3dEamcItynYxqF1YB4jf1wiMOZfZh4BLL7o=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=SrrTh+A7pxpeqkTyaiE26OuOyqywy7E7fIMmq8UZEWDeTXEz20a0CmOb5bTxwQEOuZlpAAxMvh2ORLd9RCiPuIvZlDbNknmGyowrbOknt2Ufy/eRslWPjqACbH3iGBQjhQkg71qtkDcmsTNnPyYVFjIYdDTNJPgPIPBi3DL4MV4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=Z+blcmK+; arc=none smtp.client-ip=46.235.227.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="Z+blcmK+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1707727763; bh=1VsQ4z1r3dEamcItynYxqF1YB4jf1wiMOZfZh4BLL7o=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Z+blcmK+YbesX4oSXgB0nnDs8q8tMFP62tHS9wmWzqmGkKKXHuMZSWX7Z8yIdrc4p M/JFWMrusIALQ6IB+F3V0TjmS8i+tNF2PN2BGVPyGAiBmV7gWLAXNnp499/LPTD6mP OAJ8HA1guaUgHOvm4M521hJpIg3WlL+SPdOQiXMWeVSStXXyCA8hlbJRqH6XZsAn8B /7TwojQIIPzAjm/v5MzpRc5UqricuAvpMtjqtRsPO46vcyrXQTU4V76ntzaicutipQ txstS5dQuLzVmFRUX0WHrnQFDLeaQqcIk6XEwWoJYbKWkNMXZA3RJAnktzJrgdy28d LW1y3zRvkX5hw== Received: from [100.113.186.2] (cola.collaboradmins.com [195.201.22.229]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: kholk11) by madrid.collaboradmins.com (Postfix) with ESMTPSA id 27262378203F; Mon, 12 Feb 2024 08:49:22 +0000 (UTC) Message-ID: <25e10072-30eb-4272-8a89-2c5240d53a1c@collabora.com> Date: Mon, 12 Feb 2024 09:49:21 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] iommu/mtk_iommu: Use devm_kcalloc() instead of devm_kzalloc() Content-Language: en-US To: Erick Archer , Yong Wu , Joerg Roedel , Will Deacon , Robin Murphy , Matthias Brugger , "Gustavo A. R. Silva" , Kees Cook Cc: iommu@lists.linux.dev, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-hardening@vger.kernel.org References: <20240211182250.12656-1-erick.archer@gmx.com> From: AngeloGioacchino Del Regno In-Reply-To: <20240211182250.12656-1-erick.archer@gmx.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Il 11/02/24 19:22, Erick Archer ha scritto: > This is an effort to get rid of all multiplications from allocation > functions in order to prevent integer overflows [1]. > > Here the multiplication is obviously safe because MTK_PROTECT_PA_ALIGN > is defined as a literal value of 256 or 128. > > For the "mtk_iommu.c" file: 256 > For the "mtk_iommu_v1.c" file: 128 > > However, using devm_kcalloc() is more appropriate [2] and improves > readability. This patch has no effect on runtime behavior. > > Link: https://github.com/KSPP/linux/issues/162 [1] > Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [2] > Signed-off-by: Erick Archer Reviewed-by: AngeloGioacchino Del Regno > --- > drivers/iommu/mtk_iommu.c | 2 +- > drivers/iommu/mtk_iommu_v1.c | 4 ++-- > 2 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > index 7abe9e85a570..9aae6eb604b1 100644 > --- a/drivers/iommu/mtk_iommu.c > +++ b/drivers/iommu/mtk_iommu.c > @@ -1264,7 +1264,7 @@ static int mtk_iommu_probe(struct platform_device *pdev) > data->plat_data = of_device_get_match_data(dev); > > /* Protect memory. HW will access here while translation fault.*/ > - protect = devm_kzalloc(dev, MTK_PROTECT_PA_ALIGN * 2, GFP_KERNEL); > + protect = devm_kcalloc(dev, 2, MTK_PROTECT_PA_ALIGN, GFP_KERNEL); > if (!protect) > return -ENOMEM; > data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN); > diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c > index 25b41222abae..45cd845d153f 100644 > --- a/drivers/iommu/mtk_iommu_v1.c > +++ b/drivers/iommu/mtk_iommu_v1.c > @@ -621,8 +621,8 @@ static int mtk_iommu_v1_probe(struct platform_device *pdev) > data->dev = dev; > > /* Protect memory. HW will access here while translation fault.*/ > - protect = devm_kzalloc(dev, MTK_PROTECT_PA_ALIGN * 2, > - GFP_KERNEL | GFP_DMA); > + protect = devm_kcalloc(dev, 2, MTK_PROTECT_PA_ALIGN, > + GFP_KERNEL | GFP_DMA); > if (!protect) > return -ENOMEM; > data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN); > -- > 2.25.1 >